Control mechanism for well pumps



March 4, 1952 WEST 2,587,795

CONTROL. MECHANISM FOR WELL PUMPS Filed NOV. 5, 1948 2 SHEETSSHEET 1 DEMAND SWITCH PUMP J. Hip/* Fig.4

JNVENTOR. James Mazz Wes? R Bade? rms/var? March 4', 1952 J. M. WEST CONTROL MECHANISM FOR WELL PUMPS 2 SHEETSSHEET Filed Nov. 5, 1948 my. a

INVENTOR. James Maff W65! Patented Mar. 4, 1952 UNITED STATES PATENT OFFICE CONTROL MECHANISM FOR, WELL PUMPS James Matt West, Fayetteville, Tenn.

Application November 5, 1948, Serial No. 58,434

20Claims. 1

The invention relates to controlmech'anism for well pumps, and more especially to a float controlled switch for this purpose.

In pumping water from wells, it is important that so much water shall not be withdrawn that the water level falls below the pumping barrel, or in other words that the well shall not be pumped dry.

The primary object of the present invention is to provide a simple, efiicient, cheap and economical device for controlling a pump in response to the level of the water in a well; this device cutting off the pump before the level of the water falls below the pumping barrel, and cutting the pump back on when the water rises above a given level substantially higher than the lower level.

Another object of the invention is to provide a device of this type which allows a wide range between the water levels at which the pump is turned on and oil".

A further object of the invention is to provide a device of this type in which the controlling float moves through only a short distance as compared to the distance between the two water levels, so that the movable member controlled by the float has an equally short movement, and the whole device can therefore be made small, light in weight and compact. The invention contemplates an arrangement in which the float stays in raised position until the lower water level is reached, then drops a short distance to actuate the switch and shut off the pump, and then stays in lowered position until the upper water level is nearly reached, rising thereafter only a short distance to actuate the switch and turn on the pump.

An additional object of the invention is to provide a device of this type in which an elongated float is used to control the switch, this float having a vertical movement which is only a small portion of its total length.

In general, the invention provides some means which yieldingly resists downward movement of the float, this means being capable of sustaining a great part of the weight of the float but giving way under the whole 'or substantially the whole weight of the float. When this yielding takes place, the float is limited to a short downward movement, such movement actuating the switch to cut off the pump. The float is then subjected k In its specific form, the invention includes a switch having a movable contact engaging a series of cam projections of a cam mounted on a turnable shaft, and a resilient connection between another camon this shaft and a lever connected to the float. The movable-contact is so arranged as to allow the shaft to turn in only one direction. The resilient connection is such as to resist the downward movement of the float until it is subjected to most'of the weight of the float, and to act as a pawl during upward movement of the float to turn theshaft in the direction allowed by the movable contact. Movement of the movable contact by the cam projections makes and breaks the circuit to the pump.

Further objects and advantages of my invention will appear more fully from the following description, especially when taken in conjunction with the accompanying drawings which form a part thereof.

In the drawings:

Fig. 1 shows a cross-section through a well to which is applied a pump and control mechanism embodying the invention;

Fig. 2 is a front view with parts broken away of the control mechanism with the float in lowered position;

Fig. 3 is a rear view thereof with parts broken away;

Fig. 4 is a side view thereof with parts broken away, with the float fully up;

Fig. 5 is a similar view with the float slightly down;

Fig. 6 is a similar view with the float about to drop;

Fig. 7 is a similar view with the float fully down;

Fig. 8 is a top plan View with parts broken away; and

Fig. 9 is a cross-section on the line 9-9 of Fig. 8.

' Fig. 1 shows the application of the device to a well. The well 2 is drawn on by a pumping barrel 4 on the end of pipe 6connected to pump 8. The pump is preferably electrically driven, being supplied with current from a suitable source through lines which may include a demand switch ID (for example, a switch responsive to the water level in a tank) and a water level control switch 12 which forms the primary object of the invention. This switch is controlled by an elongated float 14 through rod E5, the length of the float being preferably substantially equal to the distance between the lower water level 16 (just above the lower end of the working barrel) and the upper water level l8. The purpose of the invention is to cut off the pump whenever the water drops to level !6, and to prevent its further operation until the water reaches level is.

The switch l2 itself is shown in Figs. 2 to 9. It includes a casing having side walls 20 and 22, front wall 24, rear wall 26, top wall 28 and bottom wall 36. Mounted in the two side walls is a circular horizontal bearing shaft 32. On this shaft or bearing is a sleeve or hollow shaft 34 carrying at one point a cam 36 (preferably of insulating material) having a plurality of cam projections 38. Adjacent to one side of this cam is a fixed electrical contact 46 having a wire 42 adapted to be connected in the pump circuit. A second wire 44 is connected to a resilient conducting blade 46, which partially overlaps both cam 36 and fixed contact 46. This blade is so located that, when it engages in the spacesbetween cam projections 38 (see Figs. 4 to 6), it engages fixed contact 40 so as to close a circuit through the switch. At the same time, because the blade is substantially tangential to the cam, it will in this position prevent clockwise rotation of cam 36 and thus of shaft 34. In any other position of cam 36 (Fig. '7), blade 46 will be pushed out of contact with contact 46 to break the circuit.

Shaft 34 carries rigid therewith a second cam 48 having cam projections 50 equal in number to those on cam 36. While the cam projections 33 have sloping leading surfaces and nearly radial trailing surfaces, projections 50 have sloping surfaces on both faces. Pivoted on shaft 34 on each side of cam 48 are plates 52 of a lever. These are connected at their ends by blocks 54, 56. The

longer lever arm extends out of the switch casing through a slot 58 in front wall 24, and the downward swinging movement of the lever is limited by adjustable stop 66. At its end, in block 56, is a hook 62 or other device for connection to float rod l5.

Block 56 also supports a plate spring 64. This as the contact blade 46.

The device hereinbefore described operates as follows:

Assuming that the water in the well is at its upper level, the parts will occupy the position shown in Fig. 4. In this position, blade 46 occupies the space between two of cam projections 38 and engages contact 46, so as to close the circuit and cause the pump to operate. Lever 52 is in its raised position, and blade spring 64 rests on the leading surface of one of cam projections 50. Float I 4 is almost entirely immersed. As the pump draws water from the well (assuming that water does not flow in at an equal rate), float I4 will tend to drop. However, it is prevented from doing so by the following: Plate 46 prevents clockwise turning of the shaft, and plate spring 64 rests on cam projection 50 with sufficient resilient pressure to prevent downward movement of lever 52 until most of the weight of the float is exerted on this lever. Therefore the float will be suspended, and the pump will continue to operate.

When the water level reaches a point near the lower end of the float, the weight of the major part of the float, now unsupported by the water, will be enough to overcome the resiliency of plate 4 spring 64, and lever 52 will turn through the position shown in Fig. 6, in which the spring is just slipping off the outermost point of projection 56. As the lever 52 turns further to the position shown in Fig. 7, the free end of plate 64 will slide down on the trailing inclined surface of the cam projection with suificient force to displace the shaft 34 counterclockwise to the position shown in Fig. 7. When this occurs, one of cam projections 38 engages contact blade 46 and moves it out of engagement with contact 46, breaking the circuit and stopping the pump.

It will be apparent that the total movement of float connection 62 has been very slight in comparison with the length of the float. As the water now rises in the well, the float will not be raised until the water nearly reaches the top level. At this time, the float will begin to rise gradually and to lift lever 52 from the position of Fig. 7 to that of Fig. 4. During this movement, blade spring 64 engages in the bottom of the recess between two of projections 50, and turns the shaft 34. As the lever 52 reaches the top of its path, cam projection 38 passes out from under contact 46, allowing the contact to engage in the next space between projections 38 and to close the circuit and operate the pump. In other words, the parts are restored to the position shown in Fig. 4.

By this operation, the water level is maintained at all times above the bottom of the pumping barrel.

While I have described herein one embodiment of my invention, I wish to be understood that I do not intend to limit myself thereby except within the scope of the claims hereto or hereinafter appended.

I claim:

l. A control switch for well pumps comprising a movable member adapted to be connected to a float, an electric circuit having circuit making and breaking means therein, means operated by each movement of said member in one direction to operate said circuit making and breaking means in one sense, means resisting movement of said member in the other direction, said last means being yieldable in response to a predetermined pull applied to said member in such second direction, said last means being ineffective 'to resist movement of said member in the first direction, and means operated by each movement of said member in such second direction to operate said circuit making and breaking means in the other sense.

2. A control switch for well pumps comprising an oscillatable member having means thereon for connection to a float, a pair of electric con- 'tacts, a member turnable in one direction only having means thereon in one position to permit closing of said contacts and in other positions to open said contacts, a connection between said oscillatable member and said turnable member, said connection including means to turn said turnable member to a position allowing aid contacts to close upon each movement of said oscillatable memberin one direction in response to movement of afloat connected thereto in one direction and to resist yieldingly movement of said oscillating member in the other direction in response to movement of such float in the opposite directionyand further including means operative'o'n saidturnable member whensaid last means yields' t'oi movesaid turnable member toa position to open said 'con'tacts.

s; Ina device as claimed in claim 2 in which said'pair of contacts includes a fixed contact and a movable contact, said movable contact being engageable with said turnable member to prevent turning thereof in one direction.

4. In a device as claimed in claim 3, said turnable member including a cam against which said movable contact engages.

5. 'In a device as claim d in claim 4, said oscillatable member being pivoted on the same axis as said turnable member.

6. In a device as claimed in claim 5, said turnable member having a second cam, and said connection including a plate spring secured to said oscillatable member and engaging said second cam.

7. In a device as claimed in claim 2, said turnable member having a cam thereon having leading surfaces and trailing surfaces, and said connection including a plate spring secured to said oscillatable member and r siliently engaging said cam surfaces.

8. A control switch for well pumps comprising a shaft mounted to turn about an axis, a pair of cams, rigidly secured on said shaft having equal numbers of cam projections, a fixed contact, a movable contact extending generally tangentially with respect to and resiliently engaging the first of said cams and adapted to engage the fixed contact and to prevent rotation of such cam in one direction when in the space between successive cam projections, a lever pivoted on said shaft adjacent the second cam, said lever being adapted to be connected to a float, a plate spring carried by said lever, said spring extending generally tangential to and resiliently engaging the second cam, said spring being circumferen tially directed in the same manner as said movable contact, said spring, when said lever is in a position corresponding to fully raised position of a float connected thereto, engaging the leading edges of one of the cam projections of the second cam with sufflcient force to resist yieldingly movement of said lever in a direction corresponding to downward movement of the float, said first cam in such position of the shaft allowing said movable contact to engage the fixed contact, said spring when such yielding resistance is overcome engaging the trailing surface of such cam projection and turning the shaft to cause the first cam to move the movable contact out of contact b with the fixed contact and allowing the lever to move to a position corresponding to a lowered position of the float, said spring when the lever moves back towards a position corresponding to the raised position of the float engaging the base of the cam projection and turning said shaft until the cam projection of the first cam disengages the movable contact and allows it to move into the space between cam projections to engage the fixed contact.

9. A pump control unit comprising a pump controlling device operable to start and stop the pump, a movable member, an elongated float connected to said member, the range of movement of the point of connection of the float to the member being relatively small as compared to the length of the float, means controlled by movement of said member corresponding to each full upward movement of the float to operate said controlling device to start the pump, means resisting movement of the member in the direction corresponding to downward movement of the float, said last means being yieldable under a pull equal to the full weight of the float but being capable of preventing substantial movement of the member under a pull equal to a substantial part of the weight of the float, and mean controlled by each full movement of the member in a direction corresponding to downward movement of the float to operate said controlling device to stop the pump.

10. A pump control unit including an electric circuit having a circuit making and breaking means therein, a movable member, an elongated float connected to said member, the range of movement of the point of connection of the float to the member being relatively small as compared to the length of the float, means controlled by movement of said member corresponding to each full upward movement of the float to operate said circuit making and breaking means in one sense, means resisting movement of the member in the direction corresponding to downward movement of the float, said last means being yieldable under a pull equal to the full weight of the float but being capable of preventing substantial movement of the member under a pull equal to a substantial part of the weight of the float, and means controlled by each full movement of the member in a direction corresponding to downward movement of the float to operate said circuit making and breaking means in the other sense.

11. A pump control unit including a pair of electric contacts, a movable member, an elongated float connected to said member, the range of movement of the point of connection of the float of the member being relatively small as compared to the length of the float, a member turnable in one direction only having means thereon one position to permit closing of said contacts and in other po itions to open said contacts, a connection between said movable member and said turnable member, said connection including means to turn said turnable member to a position allowing said contacts to close when said movable member moves in one direction in response to each upward movement of the float and to resist yieldingly movement of said movable member in the other direction in response to downward movement of such float, and further including means operative on said turnable member when said last means yields to move said turnable member to a position to open said contacts.

12. A pump control unit including a pair of electric contacts, a movable member, an elongated float connected to said member, the range of movement of the point of connection of the float to the member being relatively small as compared to the length of the float, a member turnable in one direction only having means thereon in one position to permit closing of said contacts and in other positions to open said contacts, a connection between said movable member and said turnable member, said'connection including means to turn said turnable member to a position allowingsaid contacts to close upon each movement of said movable member in one direction in response to upward movement of the float and to resist yieldingly movement of said movable member in the other direction under a load less than a substantial part of the weight of the float, said last means yielding to the full weight of the float, and said connection further including means operative on said turnable member when saidlast means yields to move said turnable member to a position to open said contacts.

13. In a device as claimed in claim 12 in which said pair of contacts includes a fixed contact and a movable contact, said movable contact being engageable with said turnable member to prevent turing thereof in one direction.

14. In a device as claimed in claim 12, said turnable member including a cam against which said movable contact engages.

15. A device as claimed in claim 14, in which said movable member is mounted to oscillate on the same axis as said turnable member.

16. In a device as claimed in claim 15, said turnable member having a second cam, and said connection including a plate spring secured to said osoillatable member and engaging said second cam.

1'7. In a device as claimed in claim 12, in Which said movable member is mounted to oscillate on the same axis as said turnable member, said turnable member having a cam thereon having leading surfaces and trailing surfaces, and said connection including a plate spring secured to said osoillatable member and resiliently engaging said cam surfaces.

18. A pump control unit including a shaft mounted to turn about an axis, a pair of cams rigidly secured on said shaft having equal numbers of cam projections, a fixed contact, a movable contact extending generally tangentially with respect to and resiliently engaging the first of said cams and adapted to engage the fixed 1 contact and to prevent rotation of such cam in one direction when in the space between successive cam projections, a lever pivoted on said shaft adjacent the second cam, an elongated float connected to said lever, the range of movement or" the point of connection of the float to the lever being relatively small as compared to the length of the float, a plate spring carried by said lever, said spring extending generally tangential to and resiliently engaging the second cam, said spring being circumferentially directed in the same manner as said movable contact, said spring, when said lever is in a position corresponding to fully raised position of a float connected thereto, engaging the leading edges of one of the cam projections of the second cam with sufficient force to resist yieldingly movement of said lever in a direction corresponding to downward movement of the float under a load less than a substantial part of the weight of the float, said first cam in 4 yielding under the full weight of the float and thereafter engaging the trailing surface of such cam projection and turning the shaft to cause the first cam to move the movable contact out of contact with the fixed contact and allowing the lever to move to a position corresponding to a lowered position of the float, said spring when the lever moves back towards a position corresponding to the raised position of the float engaging the base of the cam projection and turning said shaft until the cam projection of the first cam disengages the movable contact and aling a shaft mounted to turn about an axis, a pair of cams rigidly secured on said shaft, a movable member extending generally tangentially with respect to and resiliently engaging the first of said cams and adapted to prevent rotation of such cam in one direction when in the space between successive cam projections, a lever pivoted on said shaft adjacent the second cam, said lever being adapted to be connected to a float, a plate spring carried by said lever, said spring extending generally tangential to and resiliently engaging the second cam, said spring being circumferentially directed in the same manner as said movable member, said spring, when said lever is in a position corresponding to full movement in one direction of a float connected thereto, engaging the leading edges of one of the cam projections of the second cam with sufiicient force to resist yieldingly movement of said lever in a di-.- rection corresponding to movement of the float in the other direction, said spring when such yielding resistance is overcome engaging the trailing surface of such cam projection and turning the shaft to cause the first cam to move and allowing the lever to move in the other direction, said spring when the lever moves back in such first direction engaging the base of the cam projection and turning said shaft.

20. A control switch for pumps including a lever osoillatable about an axis and adapted to be connected to a float, circuit making and breaking means, means responsive to each full movement of said lever in one direction to operate said circuit making and breaking means in one sense, a cam member mounted on the same axis as said lever, means to prevent rotation of the cam member in such direction, a spring blade on said lever engaging said cam and resiliently but yieldably resisting movement of the lever in such direction, said blade turning the cam when the lever, moves in the other direction, and means responsive to each full movement of the lever in the other direction to operate said circuit making and breaking means in the opposite sense.

JAMES MATT WEST.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 531,961 Parker et al. Jan. 1, 1895 1,311,244 Pippin July 22, 1919 1,628,222 Berth May 10, 1927 1,666,498 Lindemann Apr. 1'7, 1928 1,838,135 Derby Dec. 29, 1931 2,220,144 Carlson Nov. 5, 1940 

